The invention relates to a continuous process for melting and refining nickel containing carbon, which consists in subjecting a column of a mixture of nickel in granular form directly with fuel to heat generated from said fuel; passing large quantities of air under excessive pressure upwardly through the entire column of nickel and fuel to assure a temperature above the melting point of the nickel, and to oxidize the carbon in the nickel; allowing the melting nickel to flow downwardly through the mass “and in contact with the air”; and drawing oif the melted nickel with more or less continuity below the column. The resulting molten nickel may be tapped or poured as required.
In thermodynamics, the melting point (or freezing point) is the temperature above which a solid can be converted into a liquid by the application of energy, at a given pressure. This temperature is also sometimes referred to as the saturation temperature.
The melting point of nickle is 1453°C. It is higher than the melting points of copper (1084°C) and aluminium (644°C), but far lower than that of metals such as tungsten (3400°C). However, unlike pure nickel, nickel alloys can operate at elevated temperatures because they form thick passivating oxide layers which resist attack by hydrogen. This is because the alloys contain other metals such as copper and zinc which melt at a lower temperature. Therefore, in order to achieve the desired melting temperature, it is necessary to weigh the three metals to ensure that they are mixed in the correct proportions.